1. Field of the Invention
The present invention relates to a method for managing information on representative audio for audio tracks recorded in a rewritable recording medium and for reproducing the representative audio to have a user know easily what contents a recorded audio track has.
2. Description of the Related Art
A disk-type recording medium such as a compact disk (CD) can store high-quality digital audio data permanently, so that it is very popular recording medium. Recently, a digital versatile disk (referred as ‘DVD’ hereinafter) has been developed as a new disk-type recording medium. A DVD can store much larger size than a CD, that is, high-quality moving picture or audio data is recorded in a DVD for much longer time. Therefore, a DVD will be used widely in the near future.
There are three types in a DVD, DVD-ROM for read-only, DVD-R for write-once, and DVD-RAM or DVD-RW for rewritable. For a rewritable DVD, the standardization of data writing format is in progress.
FIG. 1 is a block diagram of an optical disk device for recording and reproducing video and/or audio data to/from a rewritable disk according to a related art.
The disk device configured as in FIG. 1 comprises an optical pickup 2 reading a signal recorded in a rewritable DVD 1 or writing a data stream processed into a writable signal in the rewritable DVD 1; a reproduced signal processor 8 restoring the read signal into compressed digital data; a decoder 9 decoding the compressed digital data into original data; a sampler 5 digitizing an inputted analog signal at a predetermined sampling rate; an encoder 4 encoding the digitized data into MPEG-, LPCM-, or AC3-formatted data; a writing signal processor 3 converting data from the encoder 4 into signals adequate to be written; a controller 6 controlling all elements to conduct a recording or reproducing operation; and a memory 7 for storing data temporally. These elements are operatively coupled.
If an analog signal is applied to the disk device of FIG. 1, the sampler 5 samples the analog signal at the predetermined sampling rate, and applies the sampled digital data to the encoder 4. The encoder 4 encodes a block of sampled data into compressed or non-compressed data of pre-specified format, for example, MPEG format for compressed or LPCM format for non-compressed, and the writing signal processor 3 converts bit trains of the formatted data into writing pulses which are applied to the pickup 2. Then, the pickup 2 writes bit information associated with the writing pulses on the recording surface of the rewritable DVD 1.
The audio data recorded continuously from recording start to stop is called a ‘track’ which is a logical unit and is different from a physical spiral track formed in a rewritable disk. If the recording operation stops after a single audio song provided from a microphone or broadcast signal has been recorded, the recorded song corresponds to a track. However, a track may contain several recorded songs if several songs are recorded continuously at one time.
The recorded audio songs, that is, all tracks are indexed by a track set information as shown in FIG. 2. Information for a track recorded newly is inserted in the track set information and information for an erased track is deleted from the track set information.
A part of a track (PoT) only specified within an audio track is able to be reproduced. Such a partial reproduction is initiated through selecting a play list which defines an audio track playback sequence. That is, a play list identifies an ordered list of predetermined songs or tracks to be played back for the user's enjoyment.
After a track has been recorded or edited, cell information (CI) is created to refer to full or part of the track. The created cell information is written in an original or a user-defined program chain information (PGCI). A play list is associated with a PGCI through the number of PGCI.
Therefore, if a play list defined by a user or created automatically after recording is selected, the controller 6 searches for a PGCI that the selected play list refers to, and reads out location information of full or part of each track written in CIs belonging to the discovered PGCI. Finally, the controller 6 moves the pickup 2 to all locations sequentially, and conducts a reproduction of the tracks or songs according to the selected.
However, since a rewritable DVD is an extremely high-capacity storage device and numerous audio tracks can be recorded in it, it becomes very difficult and time consuming to find a track containing a desirable song or sound after many audio tracks have been recorded.